| aberrant bundles | A group, or groups, of fibres from the corticobulbar or corticonuclear tract, directed to each of the motor nuclei of cranial nerves. (05 Mar 2000) |
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| aberrant complex | An anomalous electrocardiographic complex, more specifically an abnormal ventricular complex caused by abnormal intraventricular conduction of a supraventricular impulse. (05 Mar 2000) |
| aberrant ducts | The superior or inferior diverticula of the epididymis. Synonym: ductuli aberrantes, aberrant ducts, ductus aberrantes, vasa aberrantes. (05 Mar 2000) |
| aberrant ductules | The superior or inferior diverticula of the epididymis. Synonym: ductuli aberrantes, aberrant ducts, ductus aberrantes, vasa aberrantes. (05 Mar 2000) |
| aberrant ganglion | A collection of nerve cells sometimes found on a posterior spinal nerve root between the spinal ganglion and the spinal cord. (05 Mar 2000) |
| aberrant goiter | Enlargement of a supernumerary thyroid gland. Synonym: struma aberrata. (05 Mar 2000) |
| aberrant haemoglobin | A mutant Hb that functions abnormally. Compare: variant haemoglobin. (05 Mar 2000) |
| aberrant obturator artery | See: pubic branch of inferior epigastric artery. (05 Mar 2000) |
| aberrant regeneration | Misdirected regrowth of nerve fibres seen for example, after oculomotor nerve injury. Synonym: misdirection phenomenon. (05 Mar 2000) |
| aberrant ventricular conduction | Abnormal intraventricular conduction of a supraventricular beat, especially where surrounding beats are normally conducted. Synonym: ventricular aberration. (05 Mar 2000) |
| aberrate | To go astray; to diverge. "Their own defective and aberrating vision." (De Quincey) Origin: L. Aberratus, p.pr. Of aberrare; ab + errare to wander. See Err. Source: Websters Dictionary (01 Mar 1998) |
| aberration | 1. <ophthalmology> Any error that results in image degradation. Such errors may be chromatic, spherical, astigmatic chromatic, distortion, or curvature of field: and can result from design or execution, or both. 2. <physics> Failure of an optical or electron-optical lens to produce exact geometrical (and chromatic) correspondence between an object and its image. In a video camera tube or cathode-ray tube, aberrations are when the (electrostatic or electromagnetic) lens does not bring the electron beam to sharply focused points uniformly on the target or screen, or to correct geometrical positions, as the beam is deflected. 3. <zoology> A term which, if used to denote a number of individuals within a species, unequivocally signifies infrasubspecific rank. See: aberration, chromatic, aberration, spherical. (09 Jan 1998) |
| aberration, chromatic | <optics> A defect in a lens or optical system due to the greater refraction of shorter wavelengths over that of loner ones at a lens surface. Hence the focal length of a simple lens is shorter for blue than for red rays. This dispersion of the wave-lengths will cause colour fringes in the image field of a lens with such an aberration. (05 Aug 1998) |
| aberration, spherical | <optics> A lens defect whereby image forming rays of one colour, passing through the outer zones of a lens come to focus at a different distance from the lens than do those of more central rays. With a simple spherical (or plano-spherical) lens the outer rays always meet the axis closer to the lens than do more central rays and the lens is uncorrected or undercorrected. When the reverse is true the lens has been overcorrected. (05 Aug 1998) |
| aberrometer | An instrument for measuring optical aberration or any error in experimentation. Origin: L. Aberratio, aberration, + G. Metron, measure (05 Mar 2000) |